Spain has roughly 32.5 GW of wind capacity across more than 1,400 wind farms and 22,000 turbines, making it one of the largest wind fleets in Europe. OpenWindCast publishes an independent day-ahead forecast of Spanish wind output and scores it daily against Red Eléctrica's own published forecast.
Averages across all zones. Every number on this page is recomputed daily from the public record below.
Great Britain has one of the largest onshore wind fleets in Europe, with most capacity in Scotland. The forecast covers GB onshore wind and is scored against NESO's own forecast, published through Elexon.
Every forecast ships with an 80% interval. This shows how often the actual output landed inside it, and how wide it was.
The Spanish fleet is concentrated in Castilla y León, Galicia, Aragón and Andalusia, and a great deal of it sits on ridges and elevated ground rather than open plain. Terrain of that kind is the classic difficulty in wind forecasting. A weather model works on a grid several kilometres wide and reports an average wind for each cell, while a turbine on a ridge crest inside that cell experiences something quite different, because the ridge accelerates the flow in a way the grid cannot represent. The effect is a limit shared by everyone forecasting the zone.
The benchmark is Red Eléctrica de España's own day-ahead wind forecast for the Spanish bidding zone, published through the ENTSO-E Transparency Platform and captured on the day it appears. Metered generation and installed capacity come from the same source, so the forecast, the benchmark and the outcome all sit on one consistent basis.
One value per day: onshore wind output at 11:00 local time tomorrow, expressed as a load factor and published before 12:00 local, ahead of the day-ahead auction rather than after it. Once REE's own forecast for that day is published it is captured and held fixed, and once the metered output is settled both forecasts are scored against it. Every day is added to the record below and nothing is removed or rewritten later, so the full history is there to be checked rather than summarised. How this is measured.
Because a percentage of actual output becomes unstable on calm days. A 50 MW miss against a 200 MW hour looks catastrophic and the same 50 MW miss against a 20 GW hour looks trivial, even though the two cost a market participant roughly the same. Normalising by installed capacity keeps every day on one scale, and it is the convention grid operators use.
No. It covers the peninsular Spanish bidding zone, which is what Red Eléctrica forecasts and settles against. The Canary and Balearic systems are separate.
Compare every zone: how accurate are European TSO wind forecasts?
Mean absolute error as a percentage of installed capacity. Lower is better.
The share of days the forecast lands closer to the metered output than the operator's own forecast.
The range the actual output should land in 80% of the time, recalibrated daily.
NESO's published day-ahead 11:00 forecast, a fixed yardstick that is never used as an input.
A forecast of wind generation for the next delivery day, issued before the day-ahead electricity auction closes at 12:00 CET. Market participants use it to decide how much wind energy to bid into the auction.
One value per zone per day: the onshore wind output at 11:00 local time on the next day, expressed as a load factor and converted to megawatts with the installed capacity the grid operator publishes. Every forecast is published in the morning, before 12:00 local time.
Each day, the absolute error of the OpenWindCast forecast and of the grid operator's own day-ahead forecast are compared on the same 11:00 target. The site reports the mean absolute error as a share of installed capacity (nMAE), the win rate, and, where official prices are available, the imbalance cost of bidding each forecast.
Benchmark forecasts, metered generation and installed capacity come from the grid operators: Energinet, Elia, Fingrid, Red Eléctrica, the four German TSOs, PSE, REN, NESO via Elexon, and EirGrid with SONI, mostly through the ENTSO-E Transparency Platform. Weather inputs come from Open-Meteo.
Yes. The dashboard and the daily verification record are public, and each zone's history can be downloaded as CSV from the forecast section. For anything else, email m.sahaf@live.com.